Keying Fix for the 2 Transistor Sinewave Oscillator from EDN Magazine

From yesterdays blog:

https://wb9kzy.blogspot.com/2025/01/a-two-transistor-sine-wave-oscillator.html

I retried keying the oscillator using the same trick I used before for the Wien Bridge oscillator:

https://wb9kzy.blogspot.com/2022/02/wien-bridge-audio-oscillator-keying_27.html

I shorted out the back-to-back diodes using a normally ON 2n7000 MOSFET:

With the key up the gate of the 2n7000 is pulled high by the 4.7k ohm resistor to the positive power supply which turns the MOSFET ON and the oscillator OFF.  Key down then shorts the gate to ground turning the 2n7000 OFF and turning the 2 transistor oscillator ON.  It sounds pretty good !

roughly 7 mS ramp up/down times

The CPO circuit uses about 1 mA key up and 3 mA key down at a 9 volt supply, 628 Hz.

The circuit can be varied from 482 Hz (1250 mV p-p):

to 1092 Hz (600 mV p-p):

but I usually go with 600 Hz (1200 mV p-p):

Very pleased with the result, was going to report it on the EDN site but it insists that my password is incorrect :(

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm